When a contractor tells you their welders are "certified," that word is doing a lot of work — and it doesn't always mean what you'd hope. On high-pressure piping and boiler connections, the welds have to meet a specific code standard, and a contractor either has the documentation to prove it or they don't. For facility managers and general contractors, knowing how to verify those credentials before the work starts protects you from failed inspections and expensive rework.
Here's what ASME Section IX actually requires and exactly what to ask for.
What ASME Section IX Is
ASME Section IX is the section of the ASME Boiler and Pressure Vessel Code that governs the qualification of welding procedures and the welders who perform them. In plain terms, it sets the standard for how a weld on a pressure-containing system must be done and proven.
It applies to the regulated, high-stakes welding on your facility — steam systems, high-pressure piping, boiler tie-ins, and pressure vessels. This is not the same as general structural or fabrication welding. When code governs the system, Section IX is the benchmark, and the paperwork behind it is what makes a weld legally defensible.
The Three Documents to Ask For
A contractor who genuinely welds to Section IX standards will have three things on hand. If they can't produce them, that's your answer.
Welding Procedure Specification (WPS). This is the written recipe for the weld — the materials, joint design, technique, and parameters the welder must follow. It defines how a specific weld is supposed to be made.
Procedure Qualification Record (PQR). This is the proof that the WPS actually works. It documents that a test weld made under that procedure was tested and passed. The WPS says how; the PQR proves it holds up.
Welder Performance Qualification (WPQ). This confirms the individual welder — not just the procedure — is qualified to execute that WPS. A valid procedure means nothing if the person welding on your system isn't personally qualified to it.
Together, these three answer the real question: is this specific weld, made by this specific welder, following a proven procedure?
Red Flags to Watch For
A few warning signs should give you pause. A contractor who talks about certification but can't produce a WPS, PQR, or WPQ is the biggest one. So is a welder whose qualifications have lapsed — WPQs have to stay current, and an expired one doesn't count. Be equally wary of a contractor who wants to sub out the code welding to someone else; every hand-off adds schedule risk and dilutes accountability for the finished work.
The strongest position for your facility is a contractor who self-performs the code welding with their own qualified people and can hand you the documentation on request.
Why This Protects Your Facility
Verifying credentials up front isn't paperwork for its own sake. A weld that fails inspection two weeks before a regulatory audit is a genuine operational problem — it means redone work, a pushed schedule, and a compliance headache you didn't budget for. The documentation is your evidence that the work was done to code, which matters for inspections, insurance, and liability if anything is ever questioned down the line.
Asking for these records signals to a good contractor that you know what you're doing. A qualified shop will have them ready. One that hesitates has told you something important.
Work With a Contractor That Self-Performs Code Welding
KO Mechanical Services performs ASME Section IX certified welding in-house on high-pressure piping, boiler connections, and pressure systems throughout the Minneapolis/St. Paul metro. We maintain documented procedures and qualified welders, with complete records available for your inspections. As a veteran-owned mechanical contractor licensed MB100229 and HC802574 — with completed work at the Metropolitan Council Metro Plant — we bring the credentials of a much larger contractor to projects other small shops can't legally touch.
Related services: ASME Certified Welding · Piping Installation · Commercial Boiler Installation